Stereoscopic range finder



5 B. E. LUBOSHEZ 2,401,693

STEREOSCOPIC RANGE FINDER Filed July 18, 1941 -1 Fig.1. 12 l2 i Benjamin E. Luboshe z INVENTOR BY W/ ATTORNEY Y aten STEREOSQOPIC RANGE FEEDER Application .l'uly 18, 194.1, Serial No. 402,987

' (on. ss as) Claims. i

This invention relates to range finders ticularly to stereoscopic range finders.

It is an object of the invention to provide a stereoscopic range finder with which readings can be made with greater ease and greater accuracy.

With ordinary stereoscopic range finders, it has been observed that greater accuracy in range determination is obtained when they are. used on moving rather than upon stationary targets. This is because it is easier to determine when two objects are at the same distance away from the observer when one of them has a transverse movement relative to the other than when both are stationary.

According to the present invention both of the stereoscopic graticules in the eyepieces of the range finder are given equal translatory movements, preferably a slow vibration in a horizontal plane, so that there is relative movement between the stereoscopic scales and the fixed target image. There is, of course, no movement along the line of sight, i. e., no movement in depth, but only a slow movement back and forth across the field so as to make it more easy to identify the position at which the target cuts through the stereoscopic scale. A more complicated arrangement for obtaining this relative movement (and for other purposes) is described in my copendlng application Serial No. 02,98, filed concurrently herewith in which the graticules are held stationary and the image is shifted by shitting the viewpoint. The shifting graticules may also be applied to the moving viewpoint range finders, described in that copending application.

An incidental advantage of any form oi the invention is that the numbering on the scales, which frequently cannot easily be deciphered in or stereoscopic range finders when covered by parts of the target, moves in and out of view, a result usually obtainable only by moving the whole instrument.

Other objects and advantages of the invention will be apparent from the following description thereof when read in connection with the accompanying drawing in which:

Fig. l. is a horizontal section of a stereoscopic range finder.

Fig. 2 shows an arrangement for carrying both sets of stereoscopic graticules on a single plate.

Fig. 3 is a perspective View of on embodiment of the invention with the housing removed.

Fig. 4 is a perspective view of the same embodimerit showing the outside.

and par- Fig. 5 shows an alternatlvearrangement for providing graticule movement.

In Fig. 1 two viewpoints of a stereoscopic range finder are provided by pentagon prisms It which reflect the light to objectives ii and roof prisms l2 and to eyepieces it behind which the two eyes it of the observer may be positioned. The eyepieces it are at interocular separation and are preferably adjustable to accommodate difierent observers. In the focus planes of the objectives H, which are also the focus planes of the eyepieces fill stereoscopic graticules are stereoscopb cally arranged on a transparent plate 89. A front view of this plate 83 is shown in Fig.2 in which the two fields it and ii respectively include stereoscopic gratlcule rulings it and i9 stereoscopically arranged, with the scale printed adjacent to the rulings or markings. When the separation of the eyepieces it is adjustable, the separation of the graticules l6 and ii. should be similarly adjustable.

According to the invention as shown in Fig. 3 the plate i3 is given transverse back-and-forth movement as indicated by double-headed arrow 24. One end of the plate I3 is resiliently held out from a. support 20 by a spring 2!. The other end is engaged by a cam 22 driven by a motor 23. As the cam 22 rotates, the plate l3 moves back and forth under the action of the spring 2 i.

The housing for this instrument is shown in Fig. 4, the main part being in the box it, the cam 22 being in the box it and the motor 23 being in the box it.

An alternative arrangement which is most con- 5 venient for providing the slow back-and-iorth movement of the plate 93 is shown in Fig. 5. In this case one end of the plate is held against springs 33 and the other end is in contact with the wheel so mounted on the upper end of a pendulum 3 3 pivoted at the point 35 and having a weight ii at its lower end. In practice the observer takes an ordinary stereoscopic reading and then starts the pendulum i3 5 swinging to give the graticules a back-and-forth movement over the object whose range is being checked. Other observers find it easier to make all readings with the graticules moving slowly back anad forth. Alternatively the weight ii is eliminated and the movement provided by a spiral sprin like the balance wheel of a clock.

The principle of this invention may be applied to all stereoscopic range finders even those with a single pair of marks or rulings which are adjustable in apparent depth. In this latter case the bacls-and forth movement is quite indepe ent oi the depth adjustment It may also be applied to the moving viewpoint type or range finder described in my copending application; se-

rial No. 402,984, filed concurrently herewith but the appended claims.

What I claim and desire to secure by Letters Patent of the United States is:

1. A stereoscopic range finder comprising a housing, two eyepieces carried by the housing at interocular separation, means in the housing for forming in the focus planes'oi the eyepleces and from spaced viewpoints, images of the object whose range is to be found, stereoscopic graticules stereosccpically positioned in the focus planes and means carried by the housing for mov- 4 ing the graticules simultaneously and transversely without altering the stereoscopic relation.

2. A range finder according to claim 1 in which the graticules for both image planes amended by a single laterally disposed plate and the moving means operates on said plate.

3. A range finder according to claim 1 in which the moving means is reciprocating for giving a back-and-forth movement tothe graticules.

4. A range finder according to claim 1 in which the moving means includes a pendulum for providing a back-and-forth movement to the graticules.

5. A stereoscopic range finder comprising a housing, two eyepieces carried by the housing at interocular separation, means in the housing for forming in the focus planes oi the eyepieces and from spaced viewpoints, images of the object whose range is to he found, stereoscopic graticules stereoscopically positioned in the focus planes and means carried by the housing for giving transverse relative movement between the image and graticules without altering the stereoscopic relation of the graticules.

BENJAMIN E. LUBOSEEZ. 

